The study participants were from the 1946 British Birth Cohort, the UK’s longest-running population-based cohort who were all born in the same week in 1946 and whose health has been tracked throughout their life.
The researchers aimed to investigate if there was a period of life when physical activity was particularly important for later-life cognitive function, in the same way that cardiovascular health in middle age appears to be more important for later cognitive health than during other times of life.
But, rather than finding that one period of life was more important than others, they concluded that starting some form of physical activity and maintaining it over a long time may be more important than the timing of this activity.
At each survey, participants were asked how often they took part in leisure-time physical activity in the last month. Possible activities included jogging, dancing, gardening and hiking as well as a range of sports. The research team grouped respondents as either not active (no physical activity in the last month), moderately active (one to four times a month) and most active (more than five times a month).
At age 69, study participants took several cognitive tests, including the Addenbrooke’s Cognitive Examination, which assesses overall cognitive state and is used to screen people for cognitive impairment. They also did a word learning test (having to recall as many of a list of 15 words as they can) and a visual processing speed test, where they were asked to cross out all instances of a particular letter in a page of text.
The researchers also looked at other factors that might explain the link between exercise and cognitive functioning. (The exact mechanism that links the two is still unclear.)
They found that, while a link remained after accounting for a number of other factors including mental health and cardiovascular health, half to two thirds of the association could be explained by three factors: education level, childhood cognition and socioeconomic background.
That is, people who engaged more in physical activity were also more likely to have taken A-levels and gone to university, had parents from a more privileged background, and done better in tests at the age of eight, and these factors may separately contribute to better cognitive function in later life. However, a separate link remained between exercise and cognitive function and the researchers said more work was needed to understand this link better.
Limitations of the study were that the study cohort were exclusively white Caucasian and that participants were more likely to drop out of the cohort if they were socially disadvantaged and less healthy. Strengths were the long follow-up period over decades and its investigation of other potential causes of better late-life cognitive function.
Wellness Secrets of a SuperAger 